Engineering High-Performance CIGS Solar Cells: Structural Design and Process Development

ABSTRACT: The development of high-efficiency copper indium gallium diselenide (CIGS) solar cells is currently driven by a dual strategy of internal structural refinement and integration into multi-junction tandem architectures. This study aims to systematically analyze the key design and optimization strategies required to overcome the 33.7% Shockley–Queisser limit of single-junction devices. The results demonstrate that bandgap engineering, particularly through double-graded “notch” profiles, significantly enhances charge carrier collection and improves overall device performance, while alkali metal post-deposition treatments effectively reduce interface recombination losses. Furthermore, integrating CIGS with perovskite top cells in two-terminal (2T) and four-terminal (4T) configurations is a promising pathway to achieving efficiencies exceeding 30%. By combining advanced vacuum-based fabrication techniques, such as the three-stage co-evaporation process, with precise optical management, CIGS technology is positioned as a versatile candidate for both high-performance terrestrial and radiation-tolerant space applications.